KVM: cleanup io_device code

We modernize the io_device code so that we use container_of() instead of
dev->private, and move the vtable to a separate ops structure
(theoretically allows better caching for multiple instances of the same
ops structure)

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Avi Kivity <avi@redhat.com>

4 files changed, 51 insertions, 27 deletions

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index 03ea2807b1f2..c4c7ec2f9d30 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -14,11 +14,15 @@
 
 #include "coalesced_mmio.h"
 
+static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev)
+{
+        return container_of(dev, struct kvm_coalesced_mmio_dev, dev);
+}
+
 static int coalesced_mmio_in_range(struct kvm_io_device *this,
                                    gpa_t addr, int len, int is_write)
 {
-        struct kvm_coalesced_mmio_dev *dev =
-                                (struct kvm_coalesced_mmio_dev*)this->private;
+        struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
         struct kvm_coalesced_mmio_zone *zone;
         int next;
         int i;
@@ -63,8 +67,7 @@ static int coalesced_mmio_in_range(struct kvm_io_device *this,
 static void coalesced_mmio_write(struct kvm_io_device *this,
                                  gpa_t addr, int len, const void *val)
 {
-        struct kvm_coalesced_mmio_dev *dev =
-                                (struct kvm_coalesced_mmio_dev*)this->private;
+        struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
         struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;
 
         /* kvm->lock must be taken by caller before call to in_range()*/
@@ -80,12 +83,17 @@ static void coalesced_mmio_write(struct kvm_io_device *this,
 
 static void coalesced_mmio_destructor(struct kvm_io_device *this)
 {
-        struct kvm_coalesced_mmio_dev *dev =
-                (struct kvm_coalesced_mmio_dev *)this->private;
+        struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
 
         kfree(dev);
 }
 
+static const struct kvm_io_device_ops coalesced_mmio_ops = {
+        .write      = coalesced_mmio_write,
+        .in_range   = coalesced_mmio_in_range,
+        .destructor = coalesced_mmio_destructor,
+};
+
 int kvm_coalesced_mmio_init(struct kvm *kvm)
 {
         struct kvm_coalesced_mmio_dev *dev;
@@ -93,10 +101,7 @@ int kvm_coalesced_mmio_init(struct kvm *kvm)
         dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
         if (!dev)
                 return -ENOMEM;
-        dev->dev.write  = coalesced_mmio_write;
-        dev->dev.in_range  = coalesced_mmio_in_range;
-        dev->dev.destructor  = coalesced_mmio_destructor;
-        dev->dev.private  = dev;
+        kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops);
         dev->kvm = kvm;
         kvm->coalesced_mmio_dev = dev;
         kvm_io_bus_register_dev(&kvm->mmio_bus, &dev->dev);
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 1150c6d5c7b8..469b9faae665 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -220,10 +220,15 @@ void kvm_ioapic_update_eoi(struct kvm *kvm, int vector, int trigger_mode)
                         __kvm_ioapic_update_eoi(ioapic, i, trigger_mode);
 }
 
+static inline struct kvm_ioapic *to_ioapic(struct kvm_io_device *dev)
+{
+        return container_of(dev, struct kvm_ioapic, dev);
+}
+
 static int ioapic_in_range(struct kvm_io_device *this, gpa_t addr,
                            int len, int is_write)
 {
-        struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;
+        struct kvm_ioapic *ioapic = to_ioapic(this);
 
         return ((addr >= ioapic->base_address &&
                  (addr < ioapic->base_address + IOAPIC_MEM_LENGTH)));
@@ -232,7 +237,7 @@ static int ioapic_in_range(struct kvm_io_device *this, gpa_t addr,
 static void ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
                              void *val)
 {
-        struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;
+        struct kvm_ioapic *ioapic = to_ioapic(this);
         u32 result;
 
         ioapic_debug("addr %lx\n", (unsigned long)addr);
@@ -269,7 +274,7 @@ static void ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
 static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
                               const void *val)
 {
-        struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;
+        struct kvm_ioapic *ioapic = to_ioapic(this);
         u32 data;
 
         ioapic_debug("ioapic_mmio_write addr=%p len=%d val=%p\n",
@@ -314,6 +319,12 @@ void kvm_ioapic_reset(struct kvm_ioapic *ioapic)
         ioapic->id = 0;
 }
 
+static const struct kvm_io_device_ops ioapic_mmio_ops = {
+        .read     = ioapic_mmio_read,
+        .write    = ioapic_mmio_write,
+        .in_range = ioapic_in_range,
+};
+
 int kvm_ioapic_init(struct kvm *kvm)
 {
         struct kvm_ioapic *ioapic;
@@ -323,10 +334,7 @@ int kvm_ioapic_init(struct kvm *kvm)
                 return -ENOMEM;
         kvm->arch.vioapic = ioapic;
         kvm_ioapic_reset(ioapic);
-        ioapic->dev.read = ioapic_mmio_read;
-        ioapic->dev.write = ioapic_mmio_write;
-        ioapic->dev.in_range = ioapic_in_range;
-        ioapic->dev.private = ioapic;
+        kvm_iodevice_init(&ioapic->dev, &ioapic_mmio_ops);
         ioapic->kvm = kvm;
         kvm_io_bus_register_dev(&kvm->mmio_bus, &ioapic->dev);
         return 0;
diff --git a/virt/kvm/iodev.h b/virt/kvm/iodev.h
index 55e8846ac3a6..2c67f5acd6db 100644
--- a/virt/kvm/iodev.h
+++ b/virt/kvm/iodev.h
@@ -18,7 +18,9 @@
 
 #include <linux/kvm_types.h>
 
-struct kvm_io_device {
+struct kvm_io_device;
+
+struct kvm_io_device_ops {
         void (*read)(struct kvm_io_device *this,
                      gpa_t addr,
                      int len,
@@ -30,16 +32,25 @@ struct kvm_io_device {
         int (*in_range)(struct kvm_io_device *this, gpa_t addr, int len,
                         int is_write);
         void (*destructor)(struct kvm_io_device *this);
+};
+
 
-        void             *private;
+struct kvm_io_device {
+        const struct kvm_io_device_ops *ops;
 };
 
+static inline void kvm_iodevice_init(struct kvm_io_device *dev,
+                                     const struct kvm_io_device_ops *ops)
+{
+        dev->ops = ops;
+}
+
 static inline void kvm_iodevice_read(struct kvm_io_device *dev,
                                      gpa_t addr,
                                      int len,
                                      void *val)
 {
-        dev->read(dev, addr, len, val);
+        dev->ops->read(dev, addr, len, val);
 }
 
 static inline void kvm_iodevice_write(struct kvm_io_device *dev,
@@ -47,19 +58,19 @@ static inline void kvm_iodevice_write(struct kvm_io_device *dev,
                                       int len,
                                       const void *val)
 {
-        dev->write(dev, addr, len, val);
+        dev->ops->write(dev, addr, len, val);
 }
 
-static inline int kvm_iodevice_inrange(struct kvm_io_device *dev,
-                                       gpa_t addr, int len, int is_write)
+static inline int kvm_iodevice_in_range(struct kvm_io_device *dev,
+                                        gpa_t addr, int len, int is_write)
 {
-        return dev->in_range(dev, addr, len, is_write);
+        return dev->ops->in_range(dev, addr, len, is_write);
 }
 
 static inline void kvm_iodevice_destructor(struct kvm_io_device *dev)
 {
-        if (dev->destructor)
-                dev->destructor(dev);
+        if (dev->ops->destructor)
+                dev->ops->destructor(dev);
 }
 
 #endif /* __KVM_IODEV_H__ */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2d9bc439d9a9..d1f9c87daa87 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2463,7 +2463,7 @@ struct kvm_io_device *kvm_io_bus_find_dev(struct kvm_io_bus *bus,
         for (i = 0; i < bus->dev_count; i++) {
                 struct kvm_io_device *pos = bus->devs[i];
 
-                if (pos->in_range(pos, addr, len, is_write))
+                if (kvm_iodevice_in_range(pos, addr, len, is_write))
                         return pos;
         }